Malicious PDF — malware analysis report

Static analysis result for SHA-256 c15640197691573f…

MALICIOUS

PDF

67.7 KB Created: 2021-09-28 09:13:03 +03:00 Authoring application: wkhtmltopdf 0.12.5 (via Qt 5.11.3) First seen: 2021-10-26
MD5: 5c84d95dff530e7db76a92b39d1525e4 SHA-1: 299b39a741fd27ea2299738a28c3c7c3814190a4 SHA-256: c15640197691573f11c49436e3a2d890e2a7b03999be6af36cc170912380ecf9
126 Risk Score

Malware Insights

MITRE ATT&CK
T1566.001 Spearphishing Attachment

The sample is a PDF file flagged by ML classifiers and ClamAV as malicious. It contains numerous embedded URLs, with one heuristic specifically identifying it as a 'PDF_SEO_DISPOSABLE_LINK_FARM' that redirects through a 'utm_term_redirector'. While no scripts were explicitly extracted, the presence of numerous external URIs and the link farm behavior strongly suggest an intent to redirect users to malicious sites, likely for phishing or malware delivery. The authoring application 'wkhtmltopdf' is also noted.

Machine Learning

  • Nyx PDF Classifier malicious score 0.9993

Heuristics 5

  • ClamAV: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0 critical CLAMAV_DETECTION
    ClamAV detected this file as malware: Pdf.Phishing.Trojan-d2568dad23a94d95-d2568dad23a94d95-10044375-0
  • Small PDF is a non-clustered link farm on disposable hosting medium PDF_SEO_DISPOSABLE_LINK_FARM
    Small PDF contains many clickable external PDF links spread thin across many distinct hosts (no single dominant host), corroborated by a utm_term SEO-redirector link and/or links parked on free/disposable content hosts. This is the 'free document/template' SEO phishing PDF family, which ranks for search queries and routes users into payload/redirect chains, rather than a normal document citation pattern. The PDF itself carries no exploit — the risk is the linked destinations.
  • External URI info PDF_URI
    PDF contains an external URL action
  • Object number defined twice with different bodies info PDF_DUPLICATE_OBJ_BODY_INCREMENTAL
    The same indirect object (N G) is defined more than once with different body bytes. First-wins and last-wins readers will resolve different content, which is a parser-confusion shape used by targeted PDFs. Body-only differences are common in benign incremental updates, so severity is raised only when the duplicate carries active content.
  • Embedded URL info EMBEDDED_URL
    One or more URLs were extracted from the document. The URL itself is not a detection — see the per-URL labels for which channel (macro, JS, link annotation, document body, ...) reached each URL.
    URL http://jumpinfit.it/userfiles/files/mixuxiboxob.pdf In PDF document text
    • https://greenvalleykerala.com/ckfinder/userfiles/files/26342199292.pdfIn PDF document text
    • http://alhambra.kopanramen.com/uploads/files/74096128631.pdfIn PDF document text
    • https://dunaweb.co/bg_image/files/tulubaxuloxinerow.pdfIn PDF document text
    • http://ferramentabelleggia.it/public/file/juvegudegefawabixuzut.pdfIn PDF document text
    • http://boki.hu/editor_up/57466410829.pdfIn PDF document text
    • https://skykharchono.mn/editor/files/43520099670.pdfIn PDF document text
    • https://palcev.ru/userfiles/file/9295341065.pdfIn PDF document text
    • https://millersexpress.com/userfiles/file/12166151942.pdfIn PDF document text
    • http://svatba-emi.com/uploads/pages/files/69070702342.pdfIn PDF document text
    • https://bokseinstituttet.dk/wp-content/plugins/formcraft/file-upload/server/content/files/161409539aeda1---46620101304.pdfIn PDF document text
    • https://adverto.ee/userfiles/file/zopiwuf.pdfIn PDF document text
    • http://chocoenglish.com/_UploadFile/Images/file/larezuboxesibokusefetuda.pdfIn PDF document text
    • https://hoovermaids.com/wp-content/plugins/super-forms/uploads/php/files/92ce979b2d00d2ff992ef36b7651f004/mefofo.pdfIn PDF document text
    • http://tubietelbar.hu/uploadfile/dezuvu.pdfIn PDF document text
    • https://universitecentrale.net/uploads/FCK_files/file/vasavi.pdfIn PDF document text
    • https://fiscconsulting.com/userfiles/file/17103869220.pdfIn PDF document text
    • http://108shiva.com/userfiles/file/In PDF document text
    • https://feedproxy.google.com/~r/Uplcv/~3/YTWXjIUwRh0/uplcv?utm_term=tekno+latest+songPDF link annotation
    • http://www.w3.org/1999/02/22-rdf-syntax-ns#In PDF document text
    • http://purl.org/dc/elements/1.1/In PDF document text
    • http://ns.adobe.com/pdf/1.3/In PDF document text
    • http://ns.adobe.com/xap/1.0/In PDF document text
    • http://ns.adobe.com/xap/1.0/mm/In PDF document text
    • http://ns.adobe.com/xap/1.0/rights/In PDF document text
    • http://dejavu.sourceforge.netIn PDF document text
    • http://dejavu.sourceforge.net/wiki/index.php/LicenseIn PDF document text

Extracted artifacts 3

Files carved from inside the sample during analysis.

FilenameKindSourceSize
font_00_sfnt_off0000a98f.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xA98F 16408 bytes
SHA-256: b842cd7bcdba1b9956bf3df7835eeca9b40d45998e37aadb3db7c56e03af686d
font_01_sfnt_off0000d32a.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xD32A 10148 bytes
SHA-256: b967800c62a8b5fd444691896cf4f8c3fc606e3b41000e799fcf614f6e988c37
font_02_sfnt_off0000ea12.bin pdf-font-stream PDF embedded font (sfnt) at offset 0xEA12 16792 bytes
SHA-256: 9d2294e344127da9ddc2b77d68b1576b6b78373885bc9da2859f180a98f2c1e1

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